The present invention relates to a composite charged particle beam apparatus that observes the cross section of a sample or prepares a thin piece sample for a transmission electron microscope (TEM), and a method of processing a sample and a method of preparing a sample for a transmission electron microscope using the same.
Because a focused ion beam apparatus can conduct highly precise micromachining, the apparatus is variously applied to micromachining including TEM sample preparation for a thin piece. In conducting such micromachining, as disclosed in Patent Reference 1, such a method is proposed that an apparatus having a scanning electron microscope and a focused ion beam apparatus combined is used for micromachining while a sample is observed (see Japanese Patent No. 2811073). Because this method is characterized in that highly precise processing can be reliably conducted while the conditions of a sample are kept track of, this method is widely conducted.
However, there are samples having the properties of which easily change because of electron beam irradiation for contraction including low dielectric constant materials for use in semiconductors having, for example. To these samples, it is difficult to apply the method that conducts focused ion beam processing while the sample is observed through a scanning electron microscope. There are many demands for highly precise micromachining even to materials having the properties of which easily change because of electron beam irradiation, and it is desired to implement highly precise micromachining to these materials. For one solution, as described in Non-Patent Reference 1, such a method is also proposed that processing is conducted while a sample is cooled (see Suzuki, “Application of Preparing TEM samples by Dual Beam FIB”, 21st Analytical Electron Microscope Symposium Abstract, pp. 69-72, 2005). However, this method has a problem that processing takes time because the operation of a sample stage has limitations and the method includes the process steps of cooling a sample and returning the temperature of the sample to a room temperature.